1. Field of the Invention
The present invention relates in general to the field of signal processing, and more specifically, to a system and method for performing sample rate conversion using a digital sample rate converter.
2. Description of the Related Art
Mixed signal systems, i.e. combined discrete-time and continuous-time systems, process discrete- and continuous-time signals. Discrete-time signals consist of data samples that have been sampled, usually digitally, at a particular sampling frequency. Continuous-time signals consist of analog signals. In some instances, different systems utilize different sampling rates such that one data sampling frequency fs0 does not match another sampling frequency fs1. Sample rate converters serve as a compatibility interface to allow coupling between a system generating an output signal at sampling frequency fs0 and a downstream system that processes signals having a sampling frequency fs1. For example, audio signals are often sampled at either 44.1 kHz or 48 kHz. Audio signal processing systems that process signals with a sampling frequency fs1 utilize a sample rate converter to convert data sampled at fs0 into data sampled at 48 kHz and vice versa.
FIG. 1 depicts a conceptual, mixed signal sample rate converter (SRC) 100. SRC 100 utilizes mixed signal technology to convert a discrete-time signal having a sampling frequency fs0 into a continuous-time signal and then resample the analog signal at a new sampling frequency fs1. Initially, SRC 100 receives discrete-time signal x(n), having a sampling frequency fs0. The digital-to-analog converter (DAC) 102 converts signal x0(n) into a continuous-time signal y0(t). An analog low pass filter 104 removes out-of-band frequencies, such as frequencies above 20 kHz for audio applications, and generates the filtered continuous-time output signal y1(t). The analog-to-digital converter (ADC) samples the continuous-time output signal y1(t) at a sampling frequency fs1 and converts the analog output signal y1(t) into a discrete-time signal y1(n).